1. Field of the Invention
This invention relates to remote commanders and, more particularly, to a novel and highly-effective general-purpose remote commander (remote control apparatus) that is suitable for remotely controlling the operation of a plurality of electronic devices such as a television receiver, a videotape recorder and the like.
2. Description of the Prior Art
Video apparatus such as a television receiver, a videotape recorder and so on have come into wide use. Most such devices are provided with a so-called remote controller or a remote commander using infrared rays or the like so that they can be remotely controlled by the user.
The problem is then presented that a plurality of such devices cannot be remotely controlled without their own remote commanders, so the user may be uncertain or confused as to which remote commander to choose for controlling a particular electronic device. Further, remote commanders have to be operated individually in their own ways and this is very cumbersome for the user. In fact, some users cannot adequately learn how to operate so many remote commanders. Therefore, it is desirable that a single remote commander (hereinafter simply referred to as a multi-commander) be designed to be capable of remotely controlling a plurality of electronic devices. Such multi-commanders are very useful in practice. By way of example, videotape recorders produced by different manufacturers are designed to have different signal systems such as a signal waveform (number of bits per word, pulse width, modulation frequency for each pulse, etc.) of a remote control signal and a fundamental format (recursive number of a signal waveform, etc.) that cause, for example, the videotape recorder to effect the recording. Also, frequently different videotape recorders, though produced by the same manufacturer, have different signal systems because they are different in type and product type number.
A multi-commander must not only sell at a reasonable price but also have a proper size and generate remote control signals compatible with various signal systems. Conventional multi-commanders are generally either of a learn-type or of a pre-programmed type, as the following table shows.
TABLE 1 ______________________________________ Classification of conventional multi-commanders Class Sub-Class Contents ______________________________________ Learn-system Nothing stored in initial setting state.fwdarw.Supply transmission signals of respective commanders to multi-commander in which signal waveforms thereof are stored.fwdarw.Reproduce and transmit signal waveforms corresponding to respective operation keys Pre-programmed- Selection- Store waveforms of transmission system type signals of all manufac- tures.fwdarw.Select manufacturer in accordance with category of apparatus by set switch.fwdarw.Trans- mit signal waveform of selected manufacturer corresponding to each key Search- Store waverforms of transmission type signals of all manufactures.fwdarw.Out- put transmission signal wave- forms in a time-series manner and store manufacturer code having signal waveform that actuates apparatus.fwdarw.Output signal wave- form of selected manufacturer corresponding to each key ______________________________________
A multi-commander of learn-type is disclosed, for example, in official gazettes of Japanese Laid-open Pat. Appln. Nos. 60-254898 and 61-23499. The pre-programmed type multi-commander is further classified into a selection-type and a search-type. The selection-type multi-commander is disclosed, for example, in official gazette of Japanese Laid-open Pat. Appln. No. 62-23700 and the search-type multi-commander is disclosed, for example, in official gazette of Japanese Laid-open Pat. Appln. No. 62-126800.
The learn-type multi-commander is designed, in the learn-type mode, to receive remote-control signal waveforms from other remote commanders and to store the signal waveforms of the remote control signals (in some cases with timebase compression of the received signal, etc.), while in the normal mode it reconstructs the stored signal waveforms in response to the key input from the pressed key and supplies the reconstructed signal waveforms as an output. This learn-type multi-commander will hereinafter be described with reference to FIG. 1.
FIG. 1 is a pictorial representation of a prior-art learn-type multi-commander that is generally designated by reference numberal 1. As FIG. 1 shows, the learn-type multi-commander 1 comprises a mode switch 2 used to select the learn mode and the normal mode, a light emitting diode (LED) 3 used to generate a signal superimposed upon infrared rays, a light receiving element 4 used to receive infrared rays from the commanders for the video apparatus, a random access memory (RAM) 5 used to store the signal waveforms of remote control signals, a liquid crystal display panel (LCD panel) 6 used in the learn mode, and operation keys 7.
When signal waveforms of remote control signals from, for example, a television receiver commander (hereinafter simply referred to as a TV commander) 8 and a videotape recorder commander (hereinafter simply referred to as a VTR commander) 10 are stored in the multi-commander 1, the mode switch 2 is connected to the L-side (learn-mode side) contact and the light-emitting portion of the TV commander 8 is placed near the front of the light receiving element 4 of the multi-commander 1. Then, the operation keys 9 of the TV commander 8 are respectively pressed down in accordance with the order of key operations displayed on the liquid crystal display panel 6. In the same way, the light emitting portion of the VTR commander 10 is placed near the front of the light receiving element 4 of the multi-commander 1 and operation keys 11 of the VTR commander 10 are respectively pressed down in accordance with the order of key operations displayed on the liquid crystal display panel 6. When the remote-control signals corresponding to all operation keys of the two commanders 8 and 10 are written in the RAM 5 and the mode switch 2 is connected to the U-side contact (usual-mode side contact), if the respective operation keys 7 of the multi-commander 1 are depressed, the corresponding remote-control signals are read out of the random access memory 5 and are emitted from the light emitting diode 3 to the TV or to the VTR in a form superimposed upon the infared rays.
FIG. 2 pictorially illustrates a selection-type multi-commander 12 according to the prior-art pre-programmed system. As FIG. 2 shows, the selection-type multi-commander 12 includes a read only memory (ROM) 13 in which there are previously stored remote-control signals of, for example, television receivers and videotape recorders of all manufacturers. In the initial setting state, if the television receiver is the product made by manufacturer A, a 5-bit code (for example, 11011) of manufacturer A is a set by a mechanical switch 14. Similarly, a 5-bit code (for example, 01001) of a manufacture who makes a videotape recorder is set by a mechanical switch 15. When any one of operation keys 16 of the multi-commander 12 is pressed down, if the operation key corresponds to the TV operation, the multi-commander 12 reads the code set by the switch 14 and reads the signal waveform of manufacturer A corresponding to the operated key from the read only memory 13 and transmits the read-out signal waveform by means of the light emitting diode 3.
The search-type prior-art pre-programmed multi-commanders include, as in the example of FIG. 2, a read only memory in which there are previously stored control signals of a plurality of apparatus to be controlled and made by all manufacturers. In the initial setting state, a control signal of a specific manufacturer is selected from the above-mentioned control signals, as shown in FIG. 3, at a time t=t.sub.0, for example, by operating mute key and channel-up key. Control signals of all manufacturers (for example, manufacturers A to Z) are then sequentially supplied as outputs to the apparatus to be controlled in a time-series manner. When the channel of the apparatus to be controlled changes (for example, at time t=t.sub.1), the multi-commander understands that the apparatus to be controlled is the product of manufacturer E and the pressed-down keys are released.. The remote-control code of manufacturer E is then written in the random access memory. Thereafter, the multi-commander reads the signal waveform of manufacturer E from the read only memory and transmits it as a signal that operates the apparatus.
The signal format of the remote-control signal will be described with reference to FIG. 3. As that figure shows, the control signal of, for example, manufacturer A is formed of a digital signal of 32 bits; the control signal of manufacture B is formed of a signal having a constant frequency which differs in each operation; the control signal of manufacturer C is formed of a single or double-burst signal of a fixed bit time; the control signal of manufacturer D is formed of a digital signal of 24 bits; and the control signal of manufacturer E is formed of a guide pulse E.sub.0, a category code E.sub.1 (a code representing the kind of apparatus such as television receiver or videotape recorder) of 5 bits and a command code E.sub.2 of 7 bits.
Of the above-mentioned prior-art multi-commanders, the learn-type multi-commander 1 shown in FIG. 1 must store the control signals corresponding to all operation keys of the respective commanders 8 and 10 in the random access memory 5 and needs a long period of time for storing the waveforms. Further, the learn-type multi-commander 1 needs the liquid crystal display panel 6 for indicating the storing order of control signals and the random access memory 5 of large capacity in which the waveforms can be stored, thus resulting in a manufacturing cost that is substantially increased.
Of the pre-programmed type multi-commanders, the selection-type multi-commander shown in FIG. 2 entails the risk that in the initial setting state, the user will operate the switches 14 and 15 erroneously. The number of setting switches must be increased in proportion to the kinds of the apparatus to be remotely controlled, thus making it difficult to expand the capacity of the multi-commander.
Further, the search-type multi-commander needs a long time to supply as outputs the control signals of all manufacturers (about 40 manufacturers at present) and will require still more time for this purpose if the number of manufacturers whose control signals are to be stored in the ROM increases; and, if an error occurs in the time at which the operation keys are released after the apparatus to be controlled begins to operate, there is then the problem that the control signal of the wrong manufacturer is supplied as an output. Thus, the correct setting cannot be achieved.